import {Geometry} from '../core/Geometry.js'
import {BufferGeometry} from '../core/BufferGeometry.js'
import {Float32BufferAttribute} from '../core/BufferAttribute.js'
import {Vector3} from '../math/Vector3.js'
import {Vector2} from '../math/Vector2.js'

// CircleGeometry

class CircleGeometry extends Geometry {
  constructor(radius, segments, thetaStart, thetaLength) {
    super()
    this.type = 'CircleGeometry'

    this.parameters = {
      radius: radius,
      segments: segments,
      thetaStart: thetaStart,
      thetaLength: thetaLength,
    }

    this.fromBufferGeometry(new CircleBufferGeometry(radius, segments, thetaStart, thetaLength))
    this.mergeVertices()
  }
}

// CircleBufferGeometry

class CircleBufferGeometry extends BufferGeometry {
  constructor(radius, segments, thetaStart, thetaLength) {
    super()

    this.type = 'CircleBufferGeometry'

    this.parameters = {
      radius: radius,
      segments: segments,
      thetaStart: thetaStart,
      thetaLength: thetaLength,
    }

    radius = radius || 1
    segments = segments !== undefined ? Math.max(3, segments) : 8

    thetaStart = thetaStart !== undefined ? thetaStart : 0
    thetaLength = thetaLength !== undefined ? thetaLength : Math.PI * 2

    // buffers

    const indices = []
    const vertices = []
    const normals = []
    const uvs = []

    // helper variables

    const vertex = new Vector3()
    const uv = new Vector2()

    // center point

    vertices.push(0, 0, 0)
    normals.push(0, 0, 1)
    uvs.push(0.5, 0.5)

    for (let s = 0, i = 3; s <= segments; s++, i += 3) {
      const segment = thetaStart + (s / segments) * thetaLength

      // vertex

      vertex.x = radius * Math.cos(segment)
      vertex.y = radius * Math.sin(segment)

      vertices.push(vertex.x, vertex.y, vertex.z)

      // normal

      normals.push(0, 0, 1)

      // uvs

      uv.x = (vertices[i] / radius + 1) / 2
      uv.y = (vertices[i + 1] / radius + 1) / 2

      uvs.push(uv.x, uv.y)
    }

    // indices

    for (let i = 1; i <= segments; i++) {
      indices.push(i, i + 1, 0)
    }

    // build geometry

    this.setIndex(indices)
    this.setAttribute('position', new Float32BufferAttribute(vertices, 3))
    this.setAttribute('normal', new Float32BufferAttribute(normals, 3))
    this.setAttribute('uv', new Float32BufferAttribute(uvs, 2))
  }
}

export {CircleGeometry, CircleBufferGeometry}
